E. R. Speyer 



131 



held the most favourable position, the short duration of the experiment, 

 for obvious reasons, preventing interposition of the traps. 



Experiment 5. Decomposition products of banana. 



Date: — September 30th-October 1st. 

 General weather conditions: — Bright, warm. 

 Duration of experiment: — 44 hours. 



Substance 



Amyl alcohol 

 Amyl acetate 

 Banana (unripe) 



Flies caught 



Amount 

 c.c. 



60* 

 60* 



Percentage 



Total 



9 41 



12 54 



1 5 



* Denotes 20 c.c. for each period. 



Five flies were found dead in the amyl acetate trap. 



100 



Experiment 6. Decomposition products of banana. 



Date:— October 5th-6th. 



General weather conditions: — Warm, dull. 



Duration of experiment: — 24 hours. 



Flies caught 



100 



Two flies were found dead in the valerianic acid trap. 



Experiment 7. 



Date :— October 2nd-3rd. 



General weather conditions: — Bright, warm. At termination, cool with some rain. 



Duration of experiment: — 69 hours. 



Flies caught 



100 



Three flies found dead in amyl acetate, 6 in amyl alcohol, and 12 in valerianic acid traps. 



Here are shown the relative attractive powers of these three liquids, 

 and it is seen that they fall into the order in which one would expect 



